3-D Mammograms — Are They Worth the Cost?

It sounds like a cool new tool for detecting tumors, but the evidence so far is scant

En español l The latest study designed to see if new 3-D mammograms can help detect more breast tumors finds that a combination of 3-D plus the standard 2-D mammography spotted more cancers and resulted in fewer false positives than 2-D alone.

The study of nearly 7,300 women, ranging in age from 48 to 71, was conducted by researchers from Australia and Italy. Like two previous studies — one in 2012 by American researchers and one earlier this year in Norway — this one was partially supported by Hologic Inc., of Massachusetts, the first company approved by the U.S. Food and Drug Administration (FDA) to make the new combination mammogram machines.

In the study, the women received both a standard mammogram and a combination of standard plus 3-D imaging. Of the 59 breast cancers detected, 39 were found by both 2-D alone and 2-D plus 3-D, while an additional 20 cancers were found only by the combination mammography.

Study coauthor Nehmat Houssami, of the University of Sydney School of Public Health, tells AARP in an email that the new research "clearly shows that when the mammogram is interpreted based on 2D and 3D images this improves breast cancer detection compared to reporting with 2D mammograms." However, she cautions that there should be no rush to change current breast screening practices, adding that there's still an "urgent need" for more studies comparing the two methods.

Related

With a standard mammogram, a woman gets two X-rays of each breast, from top to bottom and side-to-side, while the breast is compressed between two rigid plates. With 3-D imaging, the machine moves around the breast in an arc, taking multiple X-rays from different angles.

One reason some tumors may not be detected on a standard mammogram is because compressing the breast causes overlapping of tissue, which can hide a cancer. The 3-D version enables radiologists to scroll through images of breast tissue a layer at a time, improving their ability to see questionable areas more clearly.

Digital breast tomosynthesis, as 3-D mammography is officially called, was approved by the FDA in 2011 in the hope that the clearer images would not only improve tumor detection but also decrease the number of times women get called back for additional tests.

The new study shows that 3-D technology "is very promising," says Barbara Monsees, M.D., who chairs the American College of Radiology's breast-imaging commission, but important questions remain. For example, she says, "Is this for women of all ages, or are there some women who might benefit more? Should it be done every time a woman is screened or less often? The study leaves many questions unanswered."